Using the data in the following table, and the fact that the correlation of A and B is 0.64, calculate the volatility (standard deviation) of a portfolio that is 80% invested in stock A and 20% invested in stock B. 16% Year 2008 2009 2010 2011 2012 2013 Realized Returns Stock A Stock B 2% 17% 30% 8% 7% 9% -7% 5% 15% 13% 32% The standard deviation of the portfolio is %. (Round to two decimal places.)